December 15, 1952

Dr. H. H. Plough
Dept. of Agriculture
Anherst College
Amherst, Mass.

Dear Dr. Plough:

I should appreciate receiving a reprint of your recent interesting
paper with Berry and McCarthy in the PNAS, in which you extend the
procedure of Zinder and Lederberg to include transduction of multiple
factors,

Lederberg has suggested that one step toward resolving the .
difference between your findings and his, with respect to multi-
plicity of transduction, would be to have me verify the growth
requirements of strains obtained in both laboratories. If this
precedure is agreeable to you I would be only too happy to be of
service. In addition, from the point of view of my own biochemical
interests I should appreciate the opportunity to look at the parent
Strains in which a single mutation has given rise to a multiple
requirement, and the progeny which retain only a portion of
euch a requirement.

I'd suggest that for our purposes it would be sufficient to
have the two parent strains, those in which the triple requirement
(arginine, methionine, aspartic acid) was split in various ways,
and those requiring isoleucine and valine separately.

With best personal regards, and greetings for the holiday
season,

Sincerely,

BDD/em Bernard Df Davis